Yeah,the technical challenge of getting something working usually end up being the easier part. Manufacturing ends up being very difficult: at a small scale,

Yeah,the technical challenge of getting something working usually end up being the easier part. Manufacturing ends up being very difficult: at a small scale, it's super expensive and at a medium to large scale, logistics becomes difficult. At every scale changes to the design (either for enhancements or EOL parts) is expensive. Injection molding dies require significant engineering, setup, and futzing-with to bring to production. More recent innovations in mfr'ing can be helpful (speed up prototyping and lower the cost of spinning molds or dies) but can't completely liberate you from the difficulties. I would love to see stuff like this succeed, but the difficulty can't be underestimated.